Empire and System-immanent Power in Historical Research Toru TAKENAKA The remarkable resonance Antonio Negri and Michael Hardt have found among Japanese historians with their Empire is significant for recent trends of the historiography here. The notion of the empire as an actor in the historical world and the concept of system-immanent power in Foucault's sense, which characterize the authors' outlook, are widely shared by their Japanese colleagues. This essay, skeptical of the usefulness of these views, will point out their limits for the historical research by reviewing the book. First, we should not lose sight of the significance of the nation state though the dimension of the interactions across the borderlines in the historical world could not be ignored. The nation state still remains a substantial actor even in the present globalizing world. Too much emphasis on the empire's role in constituting the modern world would lead to underestimating its role. Secondly, the concept of system-immanent power is too minute and comprehensive at once to be operative as an analytical instrument. The synchronic concept, borrowed from the semiotic discourse analysis, is basically not suitable for the diachronic examination by the historian.